It's conceivable that Galadriel was more or less on par with the istari - but I'm guessing she was a notch below Saruman and Gandalf the grey - and very likely that they viewed each other as equals. In any case, she was probably superior in some ways and inferior in others. There are several examples of high-elves surpassing more potent beings. Sauron could not have made the palantiri and even the Valar could not have created the Silmarilli. Could the wizards have replicated Galadriel's mirror? Or captured the light of Eärendil?

There's reason to believe Galadriel was more perceptive than they were. She saw the darkness in Saruman, while Gandalf and Radagast apparently did not. Gandalf spent months with Boromir, but could not sense his desire for the one ring, whereas Galadriel knew the first time she laid eyes on him. She knew Gandalf was in trouble when he fell in Moria and sensed his return. She perceived the dark lord's mind concerning the elves, but he could not perceive hers.